Noritz's most efficient commercial tankless heaters, the next generation in tankless technology - condensing heaters. NCC1991 is the new LowNOx version of NCC199. This innovation utilizes a dual heat exchanger, a fusion of stainless steel and copper heat exchangers. The 100% stainless steel component captures the residual heat from the exhaust temperature to preheat the incoming water before it runs through the main copper heat exchanger. This results in dramatic reduction of carbon dioxide and increases the heater's efficiency level to over 93%! Another benefit of this technology is lower exhaust temperatures, which means less costly PVC can be used for its venting.

>> ATTENTION!!! 3" or 4" PVC venting can only be used on condensing heaters.